IP-Centrex Systems : Alcatel

Five major telecommunications equipment manufacturers, namely Alcatel, Ericsson, Lucent, Nortel, and Siemens have been able to supply Centrex solutions, based on their respective digital CO systems, for the last decade. Three other significant public exchange manufacturers—Fujitsu, Marconi, and NEC—have not supplied Centrex software in the past and do not appear to be interested in delivering IP-Centrex systems (although NEC was one of the early suppliers of IP-PBXs).

The product descriptions that follow are not intended to be exhaustive but should give a good indication of what systems are available to deliver hybrid and full IP-Centrex from a number of vendors. The hybrid, evolutionary approach extends the life and depreciation time of legacy class 5 switches, but retains proprietary technology in the network and limits the integration of new applications. The softswitch-based, full IP-Centrex, approach can be disruptive for the service provider and its customers. This approach may also be risky if the softswitch comes from a smaller company that has had time only to develop a limited set of the popular Centrex features.

Alcatel includes a Centrex offering on its model 1000 central office, but at the time of this writing had not made any announcement regarding IP-Centrex. Alcatel is not a major vendor of Centrex systems; it has implemented a limited form of Centrex in a few countries and planned for Centrex service with several South American telcos.

The company has developed the powerful 5000 series of softswitch platforms, of which the 5020 is a signaling server and the 5424 is designed for off-loading switched data traffic from the voice network to the Internet. The model 5000 is a class 5 switch server, with a typical network topology as shown in Figure 1.


Figure 1: Network topology with Alcatel 5000 softswitch.

This 5000 softswitch can process 5 million busy hour call attempts (BHCA) and grow to 1 million virtual ports, delivering voice over IP or ATM and interfaces to the SS7 network. The softswitch in Figure 3.1 is shown with integrated access devices (IAD) on the customers' premises, providing 16 voice channels over one digital subscriber line (DSL).